A coepoeatioh



1929. E. B. THURSTON 1,738,214

DETERMINED TRAVEL SAFETY CONTROL Filed May 20, 1925 T E S era ERNEST B.THURSTON, F TOLEIDG, OHIO, ASSIGNOR T0 THE HA'UGHTQI'I a MACHINECOMPANY, 01F TOLEDO,

OHIO, A GORPORATION OF 015.10

DETERMINED TRAVEL SAFETY CONTROL Application filed May 20,

This invention relates to travel control means for elevators.

This invention has utility when incorporated in traction elevators forrendering the drive ineffective at predetermined point as when thetravel limit is reached or approached by the car or its counter-weight.

Referring to the drawings:

Fig. 1 shows an embodiment of the invention for the up and down controllimits of the car;

Fig. 2 is a detail view of one of these safety controls for effectingslippage or loss of traction; and

Fig. 3 is an end view of the grip of the control of Fig. 2.

Motor 1 is shown as having driving shaft 2 effective through worm 3 fordriving worm wheel l on shaft 5 carrying traction drum 6 u about whichextends cable having reach 7 to counter-weight 8 and reach 9 to elevatorcar 10, which car is movable up and down in elevator shaft 11 betweenlandings 12, 13, 1 1.

In the upper portion of the elevator shaft 11 fixed fulcra 15 areprovided for levers 16 carrying counter-weights 17 for holding jaw 18normally away from a descending reach of a cable. Opposing the jaw 18 isfixed jaw 19. As the counter-weight 8 ascends to approach a limit oftravel, this device may be effective for holding the car 10 againstbeing driven into a final hatch limit at the bottom of the elevatorshaft 11, for this counter-weight 8, while ascending, strikes the lever16 and thus rocks such lever 16 to cause supplemental arm 20 to actthrough spring 21 to yieldably urge the jaw 18 against the fixed jaw 19to grip cable reach 9. The load of the car 10 is thus transferred fromthe drum 6 to this grip 18, 19. The continual driving action of themotor 1 has a tendency to crowd the cable from reach 7 toward the reach9. However, as there is thus relatively little load upon the reach 9 atthe drum, the discrepancy between the loads upon the two reaches is sogreat that the drum slips beneath the cable and does not drive itfurther. This means that in those instances wherein the motor 1 maycontinue to drive after the elevator has reached a safety limitposition, no disaster may arise there- 1925. Serial No. 31,698.

from, for the counter-weight 8 holds the cable or cables against thetraction drum 6 while the grips 18, 19, have served to relieve the drum6 from th load opposing the counter-weight 8 to such an extent that theturning of the drum does not move the cable.

In practice, the drive cable may be effective to hold its traction in aV-groove of the traction drum when the ratio between the loads is as lowas four to one. If the cable or cables be greased, this ratio drops toin the region of two to one. Wrapped cable traction may be as low aseight to one. In long elevator shafts there is a factor in changing thisratio due to the length of cable extending, in the longer reach. Suchmay be a factor of hazard and as herein disclosed the device is designedto become effective as to such'longer reach and not only remove the loadof such reach in itself, but the load carried thereby, either the car 10when the car has reached its down limit or counterweight 8 when the carhas reached its upper limit. For example, if reach 8 has a load of onethousand pounds and reach 9 a load of four thousand pounds and the clampon reach 9, after it is closed by the upward travel of thecounterweight, allows a tension of thirty pounds to be transmittedthrough it to reach 9 at the driving drum, the ratio between the loadson reaches 8 and 10 becomes over to 1, so that the drum may continue toturn without moving the cable. When the actual weight of the de scendingload, whether the counterweight or the car, is gradually taken up by anoil or spring buffer or other known stopping means, this invention iseffective in supporting the weight of the cable and thus preventing thefurther lifting of the ascending load, which may occur if the entireWeight of the descending reach is suspended from the driving drum.

vV hat is claimed and it is desired to secure by United States LettersPatent is 1. An elevator installation comprising a driving drum, powermeans to rbtate the drum, a cable in frictional engagement with the drumand having a reach on each side thereof, a load on each reach exertingtension thereon, and a device adapted to engage a reach between its leadand the drum and lessen the tension exerted by the load upon the reachbetween the device and the drum and thereby lessen the friction betweenthe drum and the cable and allow the drum to continue turning withoutfurther movement of the cable.

2. An elevator installation embodying a driving drum, power means torotate the drum, a cable in frictional engagement with the drum andhaving a first reach, a car carried by said reach, said cable alsohaving a second reach, a counter-weight carried by the second reach, andmeans for rendering the drum ineffective by disturbing the ratio between the reaches as to loading transmitted to the drum, independentlyof the car or counterweight.

3. An elevator installation comprising a driving drum, a cable infrictional engagement with the drum and having a reach on each sidethereof, a load on each reach exerting tension thereon, a device adaptedto engage a reach between its load and the drum and lessen the tensionexerted by the load upon the reach between the device and the drum, andmeans operating the said device when the load upon the other reacharrives at a predetermined limit in its approach to the drum.

4. An elevator installation comprising a driving drum, a cable infrictional engagement with the drum and having a reach on each sidethereof, a load on each reach exert in'g tension thereon, means to applyfriction to a reach between its load and the drum, and a device foroperating said friction means when the load upon the other reach arrivesat a predetermined limit in its approach to the drum. 7

5. An elevator installation comprising a driving drum, a cable infrictional engage m'ent with the drum and having a reach on each sidethereof, a load on each reach exerting tension thereon, means to applyfriction to a reach between its load and the drum, and a yieldingoperating device for said means engageable by the load on the otherreach, as it approaches the drum.

6. An elevator installation comprising an elevator shaft, a driving drumat the top of the shaft, a cable passing over the drum and having adownwardly directed reach on each side of the drum, a car carried by onereach, a counterweight carried by the other reach,and a device for eachreach adjacent the drum adapted to relieve its respective reach oftension at the drum when the load of the other reach approaches the drumto a predetermined extent.

7 An elevator installation comprising an elevator shaft, a driving drumat the top of the shaft, a cable passing over the drum and having adownwardly directed reach on each side of the drum, 2, car carried byone reach,

a counterweight carried by the other reach, a

clamp for the counterweight-reach adjacent the drum, and a clamp-closingmember adapted to be engaged by the car as it approaches the drum.

8. An elevator installation comprising an elevator shaft, a driving drumat the top of the shaft, a cable passing over the drum and having adownwardly directed reach on each side of the drum, a car carried by onereach, a. counterweight carried by the other reach, a clamp for thecar-reach adjacent the drum, and a clamp-closing member adapted to beengaged by the counterweight as it approaches the drum.

9. An elevator installation comprising a driving drum, a cable passingover the drum and having a reach suspending and terminating at a car andanother suspending and terminating at a counterweight, a device adjacentthe drum adapted to sustain the weight of a reach therebelow, and meansfor operating said device when the load connected with its reachapproaches its lower limit.

10. An elevator system comprising, two

movable bodies in the hatchway, a hoisting rope connecting said movablebodies, and a safety appliance mounted in the hatehway comprising meansfor gripping the hoisting rope, and means for normally retaining saidgripping means in its inoperative position, said retaining means beingarranged to be actuated by one of the movable bodies to cause theapplication of the gripping means.

11. An elevator system comprising, two movable bodies in the hat'chway,a driving sheave, roping connecting the movable bodies and passing oversaid driving sheave, and means cooperating with saidroping to cause thestopping of one of said bodies with substantially gravity retardation.

12. In an elevator system, a movable body in the hatchway, a hoistingdrum positioned in the upper portion of the hatchway, flexible hoistingmeans extending from said hoisting drum to said movable body, and meansmounted in the hatchway near the hoisting drum for gripping saidflexible hoisting means to effect the stopping thereof.

13. In an elevator, a car, flexible means for moving the car, drivingmeans for said flexible means, and means operative, when the car ismoved to a predetermined limit, to grip and stop said flexible meansregardless of continued motion of said driving means.

14. In an elevator hatchway, a moving system comprising two movablebodies, flexible hoisting means connecting said bodies, and automaticmeans operating directly upon upon said hoisting means to cause thestopping of a portion of said system.

15. An elevator system comprising, two oppositely movable bodies in thehatchway, flexible hoisting means connecting said movable bodies, andautomatic means for grippin said hoisting means for causing the stoppingof the ascending body with substantially gravity retardation.

16. An elevator system comprising, two movable bodies in the hatchway,flexible hoisting means connecting said movable bodies, and automaticmeans for gripping said hoisting means to cause the stopping of aportion thereoi.

17. An elevator system comprising, two movable bodies in the hatchway,flexible hoisting means connecting said movable bodies, and automaticmeans for gripping said hoisting means as the descending body approachesits normal lower limit.

18. In an elevator system, a movable body in the hatchway, flexiblehoisting means for supporting said movable body, and automatic meansmounted in the hatchway for gripping said hoisting means to effect thestopping thereof.

19. In an elevator system, a movable body in the hatchway, a hoistingdrum positioned in the upper portion of the hatchway, a hoisting ropeextending from said hoisting drum to said movable body, means mounted inthe hatchway near the drum for gripping the rope and automatic means foroperating said gripping means when said body descends to a predeterminedpoint.

In Witness whereof I al'fix my signature.

ERNEST B. THURSTON.

